In a feat of modern alchemy, scientists have used a beam of vaporized titanium to create one of Earth’s heaviest elements – and they believe the new method could pave the way for even heavier horizons.
This is the first time that this new technique, which involves heating a piece of the rare isotope titanium-50 to nearly 1,650°C (3,000°F) to release ions that are directed toward another element, has successfully produced a superheavy element, livermorium.
Livermorium was first synthesized in 2000, and it is not the heaviest element created by man (that would be oganesson, atomic number 118).
So why the discovery of a few livermorium atoms at Lawrence Berkeley National Laboratory, those who follow the periodic table will ask? Livermorium is “so Y2K” and has only 116 protons.
But fusing a beam of titanium with plutonium to create livermorium is just a test run for much bigger (or rather heavier) things. Scientists are hoping to create an element that will be the heaviest ever produced: unbinilium, with 120 protons.
“This reaction had never been demonstrated before, and it was essential to prove that it was possible before we embarked on our attempt to make 120,” says Berkeley Lab nuclear chemist Jacklyn Gates, who led the research.
Calcium 48, with its 20 protons, is the reference beam because its “magic number” of protons and neutrons makes it more stable, helping it fuse with its target.
Titanium 50 is not “magic,” but it has the 22 protons needed to reach these heavier atomic weights, without being so heavy that it simply falls apart.
“This was an important first step in trying to create something a little simpler than a new element to see how going from a calcium beam to a titanium beam changes the rate at which we produce these elements,” says physicist Jennifer Pore of Berkeley Lab.
“The creation of element 116 with titanium validates that this production method works and we can now plan our hunt for element 120.”
It took 22 days of operation for the team at Berkeley Lab’s 88-inch cyclotron, which accelerates heavy titanium ions into a beam powerful enough to fuse with its target. At the end of it all, it produced only two paltry atoms of livermorium.
Creating unbinilium with this method, by aiming the beam at californium-249, will be much faster than previous routes could offer, but it will still be a long-term task.
“We think it will take about 10 times longer to make 120 than 116,” says Berkeley Lab nuclear physicist Reiner Kruecken.
It marks a return to the race for superheavy elements for the U.S. Department of Energy’s Berkeley Lab, a leader in element discovery during the 20th century.
Scientists around the world have been racing to produce unbinilium since at least 2006, when a Russian team at the Joint Institute for Nuclear Research made the first attempt. Scientists at the Helmholtz Centre for Heavy Ion Research GSI in Germany made several attempts between 2007 and 2012, but without success.
Today, as researchers from the United States, China and Russia embark on the adventure, one wonders what exactly the future applications might be.
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“It’s really important that the United States gets back into this race, because superheavy elements are very important scientifically,” nuclear physicist Witold Nazarewicz, who was not involved in the research, told Robert Service. Science.
Element 120 is close to the theoretical “island of stability,” a haven for superheavy elements where half-lives are luxuriously long, thanks to their “magic numbers” of protons and neutrons.
These stable, long-lived superheavy elements should offer scientists the opportunity to study the extremes of atomic behavior, test nuclear physics models, and trace the limits of atomic nuclei.
This document has been submitted to Physical examination letters, and is available as a preprint on arXiv.
